Gemstone cut with improved characteristics

Abstract

A gemstone cut is provided with a strategic placement of facets that optimizes the three dimensional optically geometric light interactions to thereby produce unique characteristics. In one embodiment, the gemstone has a crown with 29 facets, a pavilion with 28 facets and a girdle with 32 facets. The crown has a table with an octagonal shape, four first star facets, four second star facets, eight kite facets, eight first upper girdle facets and four second upper girdle facets. The pavilion can have eight pavilion facets, eight intermediate pavilion facets, eight first lower girdle facets and four second lower girdle facets. The girdle can have 32 facets including four sides each having seven facets and four facets at the corners of the gemstone interspaced between the side facets. The gemstone has four-fold mirror-image symmetry.

We claim:  
     
       1. A gemstone comprising:
 a crown having exactly 29 crown facets and four corners, said crown comprising
 one table facet that is an octagonal shape; 
 four first star facets; 
 four second star facets, wherein said four first star facets and said four second star facets are in an alternating arrangement and each are immediately adjacent said one table facet; 
 eight kite facets; 
 eight first upper girdle facets; and 
 four second upper girdle facets wherein one of each of said four second upper girdle facets is located midway between two of said four corners; 
 
 a pavilion having 28 pavilion facets, said pavilion comprising:
 eight primary pavilion facets; 
 eight intermediate pavilion facets being arranged in pairs; 
 eight first lower girdle facets being arranged in pairs; and 
 four second lower girdle facets being equally spaced apart; and 
 
 a girdle having exactly 32 girdle facets, said girdle comprising:
 four sides each having seven facets; and 
 four girdle corner facets, 
 wherein:
 the slope of each of said seven facets of each of said four sides has a slope of approximately 90 degrees, 
 an amount of light entering through said crown is reflected by said pavilion and exits from said crown, wherein in an area of approximately 14% of said crown a portion of said amount of light that exits from said crown does so at an angle between about 45 degrees and horizontal, and 
 said crown, said pavilion and said girdle provide a unique pattern. 
 
 
 
     
     
       2. The gemstone of  claim 1  wherein
 said crown has a crown height and said gemstone has a gemstone height, said gemstone having a ratio of said crown height to said gemstone height, the ratio of said crown height to said gemstone height being approximately 0.169. 
 
     
     
       3. The gemstone of  claim 1  wherein
 said pavilion has a pavilion height and said gemstone has a gemstone width, said gemstone having a ratio of said pavilion height to said gemstone width, the ratio of said pavilion height to said gemstone width being approximately 0.552.